1. Field of the Invention
The present invention relates to a vibration-damping device, and more specifically to a vibration damping-device for pumps mounted in vehicles.
2. Description of the Related Art
Recently, in order to reduce undesirable effects on the environment, hybrid vehicles, electric vehicles and other non-gasoline powered vehicles have been developed. In these vehicles, water pumps are used for cooling inverters, which are provided in motors serving as power sources. The rotation of the water pump components causes vibration that is transmitted to vehicle compartments to cause noise therein.
As shown in FIGS. 1 and 2, a water pump 10 normally includes a main body 12 and a leg 14, which has a generally trapezoidal section and is provided at the bottom of the main body 12. The water pump 10 is secured to a side member M of a vehicle by inserting the leg 14 in retaining members 16 provided on an upper surface of the side member M. A plurality of annular projections 18 provided in the side faces of the main body 12 connect to water hoses H. With this arrangement, the water pump 10 is secured directly by the retaining members 16 provided in a vehicle body, and, consequently, multiple-frequency vibration of the water pump 10 is transmitted to the vehicle compartment via the side member M. This transmitted vibration is undesirable noise.
This noise is not a serious problem in conventional-engine vehicles because the noise is drowned out the engine itself, which causes even greater noise. However, in hybrid vehicles with the engines off, and in electric vehicles, such transmitted noise is a serious problem.
Therefore, there is a need to provide a vibration-damping device for a pump that is mounted to a vehicle which is capable of decreasing the transmission of noise to the passenger compartment.
Accordingly, the present invention provides a vibration-damping device for supporting a pump installed in a vehicle, the vibration-damping device comprising a cushion member, a pump mounting member, and an elastic support member. The cushion member supports the pump, and includes holding portions each with a slit formed between an upper and lower surface thereof for insertion therein of end edges of a pump extension member that extends from the pump. The pump mounting member includes inverted L-shaped cross-section retaining portions provided on an upper surface thereof, the supporting portions being disposed between the retaining portions and the upper surface of the pump mounting member to retain the cushion member to the pump mounting member. The elastic support member engages a lower side of the pump to provide support against lateral deflection of the pump.
Since the cushion member is provided between the main body of the pump and the pump mounting member, vibration caused by the rotation of the pump""s internal components, particularly multiple-frequency vibration, is absorbed to greatly reduce the transmission of noise to a vehicle compartment. In addition, since the cushion member is provided to cover and hold end edges of the leg of the pump, the pump is rigidly supported to prevent it from coming loose or disengaging from the pump mounting member, and the pump is also supported in a vibration-damping condition against input of the vibrations from various directions to enhance the vibration-damping effect. By virtue of the support member, the pump is prevented from undesirably leaning due to the deviation of the center of gravity of the pump, to decrease factors causing eccentricity of the pump, and reduce the effect of hose pulsations. Consequently, by virtue of the cushion member and the support member, the transmission of noise to the vehicle compartment is reduced.